This invention relates to an automatic web splicing and feeding apparatus for feeding a web of paper, fabric or the like from a web pay out roll to a web working machine such as a rotary press or a web coater without reducing the speed of feeding the web to the web working machine at a time when a web wound about one web pay out roll is spliced to that of the other web pay out roll.
Generally, the prior art automatic web splicing and feeding apparatus can be classified into a stationary type apparatus and a pre-drive type apparatus.
In the stationary type apparatus, a web of one web roll which has been payed out is stopped at a web splicing position where a next new web is to be spliced to the trailing end of the first mentioned web. Prior to this operation, since the web roll is held at a stationary position remote from the splicing position, a shaft is inserted into a central hole of the new web roll and the both ends of the shaft projecting beyond the hole are lifted by using a hoist or the like, to a working or pay out position while observing the position of the web roll with the eyes of an operator. After mounting the web roll to the working position, and starting the feeding of the web, when the diameter of this web roll is reduced to a predetermined value, the web is stopped to splice its trailing end with the leading end of the new web. At this time the leading end is coated with an adhesive and bonded to the trailing end of the stopped web. After bonding the web of the old web roll is cut and feeding of the new web to a web working machine such as a rotary press or a web coater is commenced. In this manner, the web is continuously spliced and fed.
However, this stationary type apparatus accompanies the following defects. (1) It is a hard labour and dangerous for workers to insert a shaft into the central hole of the web roll and lift it to the working position. (2) It is considerably difficult to automatically mount the web roll to the working position. (3) The use of a lifting device such as a hoist requires more work which reduces working efficiency. (4) It is dangerous to raise the new web roll to the working position located at a considerably high level.
On the other hand, in the pre-drive type apparatus which includes two or three rotatable arms, when it is required to mount a new web roll, these arms are rotated to the position above the web roll laid on a web lifting device and the lifting device is then raised to attach the web roll to the arms. Thereafter, the arms are rotated to a web splicing position for splicing the web now being payed out with the leading end of a new web and the new web roll is then pre-driven until the peripheral speed of the new web roll comes to coincide with the feeding speed of the web now being payed out. Upon coincidence of these speeds, the leading end of the new web coated with an adhesive is press bonded to the trailing end of running web and the remainder of the running web is cut thereby continuously feeding the new web to the working machine.
However, this pre-drive type apparatus also accompanies the following defects. (1) It is necessary to use a device for coinciding the peripheral speed of the new web roll with the feeding speed of the web of the preceding or running web. (2) There is a fear of failing in web splicing if a web roll is not in a perfect cylindrical form or its surface is wavy due to the condition of storage. (3) There is a fear of getting loose the new web roll in the pre-drive operation. (4) Since the arms are rotated while the web is fed to the web working machine, a slip ring has to be used for feeding power to electric devices contained in the arms. Moreover, the construction of the apparatus is complicated because it is necessary to use a pneumatic source for driving an air cylinder and a rotary joint for cooling water, and the maintenance of these elements requires troublesome works.